================================================================== BUG: KASAN: slab-use-after-free in rt_spin_lock+0x83/0x400 kernel/locking/spinlock_rt.c:56 Read of size 1 at addr ffff888038689200 by task syz.3.94/6456 CPU: 1 UID: 0 PID: 6456 Comm: syz.3.94 Not tainted syzkaller #0 PREEMPT_{RT,(full)} Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/13/2026 Call Trace: dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:378 [inline] print_report+0xba/0x230 mm/kasan/report.c:482 __kasan_check_byte+0x2a/0x40 mm/kasan/common.c:574 kasan_check_byte include/linux/kasan.h:402 [inline] lock_acquire+0x84/0x330 kernel/locking/lockdep.c:5842 rt_spin_lock+0x83/0x400 kernel/locking/spinlock_rt.c:56 spin_lock include/linux/spinlock_rt.h:44 [inline] __wake_up_common_lock+0x2f/0x1e0 kernel/sched/wait.c:124 snd_pcm_post_stop sound/core/pcm_native.c:1551 [inline] snd_pcm_action_single sound/core/pcm_native.c:-1 [inline] snd_pcm_action sound/core/pcm_native.c:1398 [inline] snd_pcm_stop+0x428/0x550 sound/core/pcm_native.c:1571 loopback_check_format sound/drivers/aloop.c:363 [inline] loopback_trigger+0xb82/0x1b60 sound/drivers/aloop.c:411 snd_pcm_do_start sound/core/pcm_native.c:1459 [inline] snd_pcm_action_single sound/core/pcm_native.c:1315 [inline] snd_pcm_action sound/core/pcm_native.c:1398 [inline] snd_pcm_start+0x43d/0x5d0 sound/core/pcm_native.c:1506 __snd_pcm_lib_xfer+0x175a/0x1d10 sound/core/pcm_lib.c:2405 snd_pcm_oss_write3+0x1bc/0x350 sound/core/oss/pcm_oss.c:1243 snd_pcm_plug_write_transfer+0x2d1/0x4d0 sound/core/oss/pcm_plugin.c:630 snd_pcm_oss_write2+0x283/0x440 sound/core/oss/pcm_oss.c:1375 snd_pcm_oss_write1 sound/core/oss/pcm_oss.c:1441 [inline] snd_pcm_oss_write+0x6d1/0xbe0 sound/core/oss/pcm_oss.c:2796 vfs_write+0x2a3/0xba0 fs/read_write.c:684 ksys_write+0x156/0x270 fs/read_write.c:738 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xe2/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f02fb3faeb9 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f02f9635028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007f02fb676090 RCX: 00007f02fb3faeb9 RDX: 0000000000004000 RSI: 00002000000012c0 RDI: 0000000000000007 RBP: 00007f02fb468c1f R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f02fb676128 R14: 00007f02fb676090 R15: 00007fffceb10158 Allocated by task 6452: kasan_save_stack mm/kasan/common.c:57 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:78 poison_kmalloc_redzone mm/kasan/common.c:398 [inline] __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:415 kasan_kmalloc include/linux/kasan.h:263 [inline] __kmalloc_cache_noprof+0x1f2/0x6b0 mm/slub.c:5780 kmalloc_noprof include/linux/slab.h:957 [inline] kzalloc_noprof include/linux/slab.h:1094 [inline] snd_pcm_attach_substream+0x5b7/0xb20 sound/core/pcm.c:938 snd_pcm_open_substream+0xbd/0x2420 sound/core/pcm_native.c:2761 snd_pcm_oss_open_file sound/core/oss/pcm_oss.c:2439 [inline] snd_pcm_oss_open+0xfc2/0x1c50 sound/core/oss/pcm_oss.c:2520 chrdev_open+0x4d0/0x5f0 fs/char_dev.c:414 do_dentry_open+0x7d0/0x1270 fs/open.c:962 vfs_open+0x3b/0x350 fs/open.c:1094 do_open fs/namei.c:4637 [inline] path_openat+0x34c9/0x3e70 fs/namei.c:4796 do_filp_open+0x22d/0x490 fs/namei.c:4823 do_sys_openat2+0x12f/0x220 fs/open.c:1430 do_sys_open fs/open.c:1436 [inline] __do_sys_openat fs/open.c:1452 [inline] __se_sys_openat fs/open.c:1447 [inline] __x64_sys_openat+0x138/0x170 fs/open.c:1447 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xe2/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Freed by task 6452: kasan_save_stack mm/kasan/common.c:57 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:78 kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:584 poison_slab_object mm/kasan/common.c:253 [inline] __kasan_slab_free+0x5c/0x80 mm/kasan/common.c:285 kasan_slab_free include/linux/kasan.h:235 [inline] slab_free_hook mm/slub.c:2540 [inline] slab_free mm/slub.c:6674 [inline] kfree+0x1bb/0x8f0 mm/slub.c:6882 snd_pcm_detach_substream+0x1e1/0x290 sound/core/pcm.c:1003 snd_pcm_oss_release_file sound/core/oss/pcm_oss.c:2398 [inline] snd_pcm_oss_release+0x184/0x250 sound/core/oss/pcm_oss.c:2577 __fput+0x45e/0xa80 fs/file_table.c:468 task_work_run+0x1d9/0x270 kernel/task_work.c:233 get_signal+0x11c3/0x1310 kernel/signal.c:2807 arch_do_signal_or_restart+0xbc/0x830 arch/x86/kernel/signal.c:337 __exit_to_user_mode_loop kernel/entry/common.c:41 [inline] exit_to_user_mode_loop+0x86/0x480 kernel/entry/common.c:75 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline] syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline] syscall_exit_to_user_mode_work include/linux/entry-common.h:159 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:194 [inline] do_syscall_64+0x2b7/0xf80 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f The buggy address belongs to the object at ffff888038689000 which belongs to the cache kmalloc-2k of size 2048 The buggy address is located 512 bytes inside of freed 2048-byte region [ffff888038689000, ffff888038689800) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x38688 head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0 flags: 0x80000000000040(head|node=0|zone=1) page_type: f5(slab) raw: 0080000000000040 ffff88813fe27000 ffffea00016f5000 dead000000000002 raw: 0000000000000000 0000000000080008 00000000f5000000 0000000000000000 head: 0080000000000040 ffff88813fe27000 ffffea00016f5000 dead000000000002 head: 0000000000000000 0000000000080008 00000000f5000000 0000000000000000 head: 0080000000000003 ffffea0000e1a201 00000000ffffffff 00000000ffffffff head: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000008 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 3, migratetype Unmovable, gfp_mask 0xd28c0(GFP_NOWAIT|__GFP_IO|__GFP_FS|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 69, tgid 69 (kworker/u8:4), ts 102373279294, free_ts 102279359916 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x228/0x280 mm/page_alloc.c:1884 prep_new_page mm/page_alloc.c:1892 [inline] get_page_from_freelist+0x28bb/0x2950 mm/page_alloc.c:3945 __alloc_frozen_pages_noprof+0x18d/0x380 mm/page_alloc.c:5240 alloc_pages_mpol+0xd1/0x380 mm/mempolicy.c:2486 alloc_slab_page mm/slub.c:3075 [inline] allocate_slab+0x86/0x3a0 mm/slub.c:3248 new_slab mm/slub.c:3302 [inline] ___slab_alloc+0xaf8/0x13d0 mm/slub.c:4656 __slab_alloc+0xc5/0x1f0 mm/slub.c:4779 __slab_alloc_node mm/slub.c:4855 [inline] slab_alloc_node mm/slub.c:5251 [inline] __do_kmalloc_node mm/slub.c:5656 [inline] __kmalloc_node_track_caller_noprof+0x2b6/0x7f0 mm/slub.c:5768 kmalloc_reserve+0x136/0x290 net/core/skbuff.c:608 pskb_expand_head+0x19d/0x1300 net/core/skbuff.c:2283 netlink_trim+0x1b3/0x2c0 net/netlink/af_netlink.c:1299 netlink_broadcast_filtered+0xd6/0x1010 net/netlink/af_netlink.c:1512 nlmsg_multicast_filtered include/net/netlink.h:1165 [inline] nlmsg_multicast include/net/netlink.h:1184 [inline] nlmsg_notify+0xf0/0x1a0 net/netlink/af_netlink.c:2593 netif_state_change+0x297/0x3a0 net/core/dev.c:1599 linkwatch_do_dev+0x117/0x170 net/core/link_watch.c:186 __linkwatch_run_queue+0x575/0x7f0 net/core/link_watch.c:244 page last free pid 5784 tgid 5784 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] free_pages_prepare mm/page_alloc.c:1433 [inline] __free_frozen_pages+0xfd0/0x1160 mm/page_alloc.c:2973 discard_slab mm/slub.c:3346 [inline] __put_partials+0x149/0x170 mm/slub.c:3886 __slab_free+0x2af/0x330 mm/slub.c:5956 qlink_free mm/kasan/quarantine.c:163 [inline] qlist_free_all+0x97/0x100 mm/kasan/quarantine.c:179 kasan_quarantine_reduce+0x148/0x160 mm/kasan/quarantine.c:286 __kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:350 kasan_slab_alloc include/linux/kasan.h:253 [inline] slab_post_alloc_hook mm/slub.c:4953 [inline] slab_alloc_node mm/slub.c:5263 [inline] __kmalloc_cache_noprof+0x188/0x6b0 mm/slub.c:5775 kmalloc_noprof include/linux/slab.h:957 [inline] kzalloc_noprof include/linux/slab.h:1094 [inline] nsim_fib6_rt_create drivers/net/netdevsim/fib.c:547 [inline] nsim_fib6_rt_insert drivers/net/netdevsim/fib.c:752 [inline] nsim_fib6_event drivers/net/netdevsim/fib.c:856 [inline] nsim_fib_event+0xf3c/0xa410 drivers/net/netdevsim/fib.c:889 nsim_fib_event_work+0x26e/0x3e0 drivers/net/netdevsim/fib.c:1493 process_one_work kernel/workqueue.c:3257 [inline] process_scheduled_works+0xaec/0x17a0 kernel/workqueue.c:3340 worker_thread+0xda6/0x1360 kernel/workqueue.c:3421 kthread+0x726/0x8b0 kernel/kthread.c:463 ret_from_fork+0x51b/0xa40 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246 Memory state around the buggy address: ffff888038689100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888038689180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff888038689200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888038689280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888038689300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================